The present disclosure relates to battery management. In particular, it relates to a virtual cell method for battery management.
Currently, a typical conventional battery pack comprises an array of battery cells connected together in parallel and in series. Ideally, these battery cells have the same internal (i.e. various over-potentials of the electrodes and separator) and external (i.e. voltage and discharge capacity) characteristics. However, this is practically not true due to battery cell defect variations as well as to different levels of degradations to the battery cells resulting from processes of manufacturing, storage, transportation, and operation. A defective or degraded battery cell has a higher over-potential (i.e. externally exhibiting as a higher internal resistance) compared to other battery cells to which the battery cell is connected in parallel. The defective or degraded battery cell tends to generate more heat, thereby causing overheating to itself and to its neighboring battery cells. This excess of heat may result in an accelerated degradation of the batteries.